Replaceable wear liners for twin screw mixers and similar machines are well known, however, prior art liners of the required "hard" material, particularly in the case where the screws were of substantial length, are frequently difficult to machine to the required tolerances and present alignment and locating problems in installation. In many cases, in attempting to minimize the degree of precision of the machining operations for producing the liners, the liners are manufactured in sections, (see for example Worz U.S. Pat. No. 4,028,027) thereby increasing the difficulty of accurately installing the liners in position within their housing.
The present invention is especially directed to a liner assembly in which the surfaces of the liner are either flat or cylindrical, minimizing the difficulties of the forming operation to a point where full length liners can be readily constructed to a high degree of dimensional precision.